On 3/26/14, 10:17 AM, "Khanh-Toan Tran" <khanh-toan.t...@cloudwatt.com> wrote:
> > >----- Original Message ----- >> From: "Sangeeta Singh" <sin...@yahoo-inc.com> >> To: "OpenStack Development Mailing List (not for usage questions)" >><openstack-dev@lists.openstack.org> >> Sent: Tuesday, March 25, 2014 9:50:00 PM >> Subject: [openstack-dev] [nova][scheduler] Availability Zones and Host >>aggregates.. >> >> Hi, >> >> The availability Zones filter states that theoretically a compute node >>can be >> part of multiple availability zones. I have a requirement where I need >>to >> make a compute node part to 2 AZ. When I try to create a host aggregates >> with AZ I can not add the node in two host aggregates that have AZ >>defined. >> However if I create a host aggregate without associating an AZ then I >>can >> add the compute nodes to it. After doing that I can update the >> host-aggregate an associate an AZ. This looks like a bug. >> >> I can see the compute node to be listed in the 2 AZ with the >> availability-zone-list command. >> > >Yes it appears a bug to me (apparently the AZ metadata indertion is >considered as a normal metadata so no check is done), and so does the >message in the AvailabilityZoneFilter. I don't know why you need a >compute node that belongs to 2 different availability-zones. Maybe I'm >wrong but for me it's logical that availability-zones do not share the >same compute nodes. The "availability-zones" have the role of partition >your compute nodes into "zones" that are physically separated (in large >term it would require separation of physical servers, networking >equipments, power sources, etc). So that when user deploys 2 VMs in 2 >different zones, he knows that these VMs do not fall into a same host and >if some zone falls, the others continue working, thus the client will not >lose all of his VMs. It's smaller than Regions which ensure total >separation at the cost of low-layer connectivity and central management >(e.g. scheduling per region). > >See: http://www.linuxjournal.com/content/introduction-openstack > >The former purpose of regouping hosts with the same characteristics is >ensured by host-aggregates. > >> The problem that I have is that I can still not boot a VM on the >>compute node >> when I do not specify the AZ in the command though I have set the >>default >> availability zone and the default schedule zone in nova.conf. >> >> I get the error ³ERROR: The requested availability zone is not >>available² >> >> What I am trying to achieve is have two AZ that the user can select >>during >> the boot but then have a default AZ which has the HV from both AZ1 AND >>AZ2 >> so that when the user does not specify any AZ in the boot command I >>scatter >> my VM on both the AZ in a balanced way. >> > >I do not understand your goal. When you create two availability-zones and >put ALL of your compute nodes into these AZs, then if you don't specifies >the AZ in your request, then AZFilter will automatically accept all hosts. >The defaut weigher (RalWeigher) will then distribute the workload fairely >among these nodes regardless of AZ it belongs to. Maybe it is what you >want? With Havana that does not happen as there is a concept of default_scheduler_zone which is none if not specified and when we specify one can only specify a since AZ whereas in my case I basically want the 2 AZ that I create both to be considered default zones if nothing is specified. > >> Any pointers. >> >> Thanks, >> Sangeeta >> >> _______________________________________________ >> OpenStack-dev mailing list >> OpenStack-dev@lists.openstack.org >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> > >_______________________________________________ >OpenStack-dev mailing list >OpenStack-dev@lists.openstack.org >http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev